Output Device

Output devices are sensor that relay data from a micro-controller or computer to a hardware that can either inform the person through sound, light or a display. This can also be a Mechanical function as well for instants a PC fan. To get a good reading we used Lysander PCB board and the PC fan what will be used in his wind tunnel project. The fans manufacture states that at 12Volts it will consume a current of 0.295 Amps. To test this we hooked the PCB Board to a lab power supply. The Voltage was set to 12 volts and the Plus and Minus were hooked up to the input pins on the board. The next thing we did was test if the had indeed wired everything correctly, insuring that the fan was than plugged in correctly as well. Having done so we pushed the switch on the power supply and checked if the board and fan would turn on.
Now that this was done we went ahead and talked about how best to measure the power consumption and how to see if the power being used by the PC fan was accurate. To do this we used the formula P=V×I. We noted that P = Power in watts(W), V = Voltage in volts (V), I = Current in amperes (A) and that we want to find the power being used. The math gave us the following result, P=12V×0.295A=3.54W. This was the consumption with in one hour. To find the what it used in one minute, to check what he now usage was we simple did the following. Energy (wh) = Power (Watts) x Time in minutes / 60min. We wanted the closest value 1 min was was taken. the result was that in one we were using O.059 Wh. Now looking at the read out of the power supply we got 0.051 Wh.

This was a good result. Now we needed to find out how much power the board was using. The fan was removed and the result was that the board was using so little current that it could be completely neglected. Plugging the fan back in we looked at the amps the fan was using once it was up to speed. In the begins the fan used more power to overcome the inertia. This can be compared to the moment you start riding a bicycle. The rider needs to over come this resistances. Once done so, the rider needs less power to to keep moving. To find out if this was also the case we used the blink function for the built-in LED but for the fan. We increased the time to 5 seconds. This gave the fan time to speed up and stop and speed up again. Giving us a good chance to see how much the current it was really using. Here we were also within the ballpark. The current being used according to the power supply read 0.201 Amps, once it was up to speed. So less than what the fans maximum of 0.295 Amps.
The interesting thing to observer was the when we hooked in a multimeter between the board and the fan to get the power usage there. Below is a video that shows that the fan once up to speed uses a lot less current. This was measured on the multimeter in mA and the result was 0.175 mA. As we can see the usage that we calculated earlier was pretty much dead on. If the need to repeat a simple test, the code can be looked at below as well as a simple sketch that shows the setup.